This week’s question was asked by Derrik Vanasse, fifth grade at La Grange Elementary School.
Teacher: Chelsey Juliot.
QUESTION: What are people made of?
Almost the entire body, about 99 percent, is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus. About one percent of the human body is composed of another five elements: potassium, sulfur, sodium, chlorine and magnesium. All 11 elements are necessary for life. The super two are oxygen, making up 65 percent of the body, and carbon accounting for a tad less than 19 percent.
Those elements make up our bones, muscles, tissue, fat, water, protein, carbohydrates, amino acids, hair, the works. The average 150-pound person comprises a minimum of 60 trace elements. Half of these are deemed essential to a healthy human.
Yes, we have tiny amounts of elements in our body that are not good for us. Those include cadmium, mercury, lead, arsenic, fluorine, barium, thallium and radium.
Every one of the elements in our body, with the exception of hydrogen, was created in stars billions of years ago. As the late astrophysicist Carl Sagan (Cosmos television series) would remind us, “You and I are literally made of star stuff.” Those elements were forged in distant galaxies shortly after the Big Bang, some 13 billion years ago. The elements come from burning and exploding stars. In a weird sort of way, we are all about 13 billion years old. And here I had hopes of making it to 85 or 90, perhaps 100 at best.
A news item in the papers a few weeks ago might have caught your attention. “Astronomers strike gold, witness massive cosmic collision” was the headline. This last August, observatories from around the world witnessed the collision of two neutron stars that “caused the most spectacular fireworks in the universe.” The Hubble space telescope got a snapshot of the afterglow.
The clash happened in galaxy NGC 4993 in the constellation of Hydra, an estimated 130 million years ago when dinosaurs roamed the Earth. It took 130 million years for light, gamma rays and gravity ripples to reach us from the constellation of Hydra. Neutron stars are formed from the collapse of a massive star after a supernova explosion, if the star is massive enough to produce a black hole. The material in a neutron star, with its electrons stripped away, is so dense a teaspoon weighs a billion tons. Truly “thy power throughout the universe displayed.”
The heavier elements were created in that distant collision. An estimated 10 billion, billion, billion dollars worth of gold. Perhaps enough to pay off our national debt! University of California Santa Cruz astronomer, Ryan Foley was quoted, “We already knew that iron came from a stellar explosion, the calcium in your bones came from stars, and now we know the gold in your wedding ring came from merging neutron stars.”
The first optical image from this collision showed a bright blue dot, the start of heavy element creation. After a day or two, the blue faded, becoming much fainter and redder. After three weeks it was completely gone.
It’s an incredible, yet humbling, idea that we and the entire Earth originated in some far distance group of stars. Even more inconceivable is that we are able to figure it out − that we have a brain and body to build the tools and use those tools to search the universe and know our place, position and time in that cosmic scheme.
Send questions and comments to: firstname.lastname@example.org.
Larry Scheckel is a retired Tomah High School physics teacher.
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